1. Field of Invention
The present invention relates generally to fuel pressure pulsation damping systems, and more particularly to a fuel pressure pulsation damping system with reduced pulsation magnitudes at resonate modes of the fuel deliver system.
2. Description of the Known Technology
Conventional methods of damping pressure pulsations in a fuel system rely solely on inclusion of a member that introduces more compliance (a “compliance member”), thereby reducing the bulk modulus of the system. This can be accomplished through the use of a conventional fuel pressure damper, an internal damper or inherent/self-damping, the latter being where a member of the fuel delivery system in fluid communication with the pulsating fuel is provided with a flexible wall or walls to absorb the pressure fluctuations within the system. The location of these compliance members generally are governed solely by manufacturing and packaging concerns.
Simply adding compliance is not always sufficient to relieve all of the objectionable pressure pulsations in the fuel delivery system however. It can also result in unwanted variation in the fuel injector performance as well as objectionable noise, vibration and harshness. In some systems where adding sufficient compliance is possible, it may not be commercially feasible or physically practical to introduce a custom designed compliant damping system. The additional compliance may make certain members too weak to function properly or require expensive materials to achieve the desired effect.
Resolving these resonant frequency issues simply by adding more compliance can result in other unwanted effects. Adding more compliance may allow more pulsations to be absorbed, but it will also result in a shift in frequency of resonant modes of the system. As compliance is increased, the frequency of resonant modes of the system shift to lower frequencies. When the frequency of the modes shift lower, higher resonant modes that were previously above the operating frequency range of the fuel system (and thus previously not a problem) may shift into the operating frequency range of the fuel system. Therefore, adding more compliance can sometimes result in more objectionable resonant frequency modes than before.
It remains desirable to provide a means of damping objectionable pressure pulsations to thereby limit the maximum operating system pulse magnitude, other than by merely adding compliance.